To provide a pipe joint installation mechanism in a selector valve in which the installation work of plural pipe joints is easy.

Output openings 35A, 35B, 36A, 36B for communicating separately with respective output ports of a selector valve 1 are provided in the vertical direction of the front surface of a port block 4 and a metal fitting inserting groove is installed on its side surface and pipe joints 5,... are inserted in these output openings respectively and an installation metal fitting 41 is inserted in the metal inserting groove. Then, an engagingly locking part provided on the metal fitting is engagingly locked to the engagingly locking grooves 38,... of the pipe joints respectively and the pipe joints are installed. The port block 4 in which the pipe joints 5... are installed and the installation metal fitting 41 are installed on the front surface of the selector valve 1 by installation bolts 48... whose heads are loosely inserted in the head insertion parts 46... of the port block.